The term "silver haloiodide" is employed in its art recognized usage to designate silver halide grains containing silver ions in combination with iodide ions and at least one of chloride and bromide ions. The term "reversal photographic element" designates a photographic element which produces a photographic image for viewing by being imagewise exposed and developed to produce a negative of the image to be viewed, followed by uniform exposure and/or fogging of residual silver halide and processing to produce a second, viewable image. Color slides, such as those produced from Kodachrome.RTM. and Ektachrome.RTM. films, constitute a popular example of reversal photographic elements. In the overwhelming majority of applications the first image is negative and the second image is positive. Groet U.S. Pat. No. 4,082,553 illustrates a conventional reversal photographic element containing a silver haloiodide grains modified by the incorporation of a small proportion of fogged silver halide grains. Hayashi et al German OLS No. 3,402,840 is similar to Groet, but describes the imaging silver halide grains in terms of those larger than and smaller than 0.3 micrometer and additionally requires in addition to the fogged silver halide grains or their metal or metal sulfide equivalent an organic compound capable of forming a silver salt of low solubility.
High aspect ratio tabular grain silver haloiodide emulsions have been recognized to provide a variety of photographic advantages, such as improvements in speed-granularity relationships, increased image sharpness, and reduced blue speed of minus blue recording emulsion layers. High aspect ratio tabular grain silver haloiodide emulsions in reversal photographic elements are illustrated by Research Disclosure Vol. 225, January 1983, Item 22534; Wilgus et al U.S. Pat. No. 4,434,226; Kofron et al U.S. Pat. No. 4,439,520; Solberg et al U.S. Pat. No. 4,433,048; Maskasky U.S. Pat. No. 4,400,463; and Maskasky U.S. Pat. No. 4,435,501. Research Disclosure is published by Kenneth Mason Publications, Ltd., The Old Harbourmaster's, 8 North Street, Emsworth, Hampshire P010 7DD, England.
U.S. Pat. No. 4,656,122 describes silver halide photographic elements capable of producing reversal images including one emulsion layer comprising a blend of tabular silver haloiodide grains and fine grains of a silver salt more soluble than silver iodide.
In U.S. Pat. No. 5,391,468, the addition of dye to high solubility fine grains which are added to an imaging emulsion layer is described. No discussion is present of inter or outerlayers. Again, in U.S. Pat. No. 5,176,990, the dual melting of a liquid emulsion to imaging emulsion layers is described.
U.S. Pat. No. 5,552,265 teaches the use of a small amount of fine grains below the bottom layer to add to the Dmin of the red recording. U.S. Pat. No. 4,614,707 also describes the use of Lippmann emulsions and Dox scavengers below the slow layer to sharpen the toe contrast.
The addition of Lippmann emulsions in interlayers to intercept inhibitor has been described in GB 1,201,110 for reversal films and in U.S. Pat. No. 4,752,701 for color negative film.
It is however, desirable for higher color saturation. Imaging dyes generally have unwanted light absorption which reduce the color saturation. Interimage effect will compensate such unwanted light absorption but more interimage effect is desirable.
It has been reported that the addition of relatively fine grains consisting essentially of a silver salt more soluble than silver iodide to an image forming layer containing tabular silver haloiodide grains can produce a combination of advantages in reversal imaging. The reversal threshold speed of the reversal photographic elements can be increased. At the same time, reduced toe region density in the reversal image as well as increases in maximum density and contrast are observed.
Multi-color photographic element typically have red, green, blue color records (in that order) above the support and interlayers in between color records. Typically a blue light filtration interlayer is added below the blue color record to reduce the blue light exposure of the green and red light sensitive emulsions. A green light filtration interlayer is added below the green color record to reduce the green light exposure of the red light sensitive emulsion.
Multi-color photographic elements typically have red, green, blue color records (in that order) above the support and interlayers in between. The above description applies to other constructions (e.g. blue, red, green three-color-record element, or red, green two-color-record element, and others).
Another way of obtaining higher color saturation is by adding a red light sensitive emulsion above the green color record; or by adding green light sensitive emulsion above the blue light color record. Such layers may contain imaging couplers or may not have any couplers. However, there are several problems with this approach:
1. The extent of color saturation increase is relatively small consequently, a large amount of the red light or green light sensitive emulsion has to be added in such an application. PA1 2. Such large amounts of emulsion addition generate unwanted light absorption by the above red light emulsion or the above green light emulsion, as such emulsion is added above the blue light filtration layer or the green light filtration layer. PA1 3. Such extra emulsions generate extra light scattering, deteriorating the sharpness of the photographic element. PA1 a) a red light, green light or blue light sensitive silver halide emulsion which is less than 10 percent of the mass of the total imaging emulsion in the element; and PA1 b) a non-image forming silver halide emulsion having a grain size less than 0.15 .mu.m, and preferably wherein the molar ratio of the grain population of the non-image forming emulsion to that of the image forming emulsion is greater than 3:2 and the surface area ratio of the non-image forming emulsion to the image forming emulsion is more than 2:1. PA1 a) a light sensitive silver halide emulsion which is less than 10 percent of the mass of the total imaging emulsion in the element; and PA1 b) a non-image forming silver salt emulsion having a grain size less than 0.15 .mu.m, and the molar ratio of the grain population of the non-image forming emulsion to that of the image forming emulsion is greater than 3:2 and the surface area ratio of the non-image forming emulsion to the image forming emulsion is more than 2:1 is formed.